force update master if it is crashed
force update master if it is crashed

When master is crashed, curl will succeed, but the http code is 500, cause nginx is actually there
So we use the get_url ansible builtin instead of curl to be able
to easily get the status code

buildbot/buildbot-infra,buildbot/buildbot-infra,seankelly/buildbot-infra,seankelly/buildbot-infra,buildbot/buildbot-infra,seankelly/buildbot-infra